Doctor's Note

For background on what platelets are, what they do, and why we should care, see Inhibiting Platelet Aggregation with Berries and Inhibiting Platelet Activation with Tomato Seeds

What else can garlic do? Check out:

What’s that about mustard powder boosting the benefits of broccoli? See my Second Strategy to Cooking Broccoli video.

For whether it’s better to cook vegetables or eat them raw, see Best Cooking Method and for a surprise update, The Best Way to Cook Sweet Potatoes.

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  • Kevin

    Wow I’m early! This is some nice information. Glad to know we can make our onions/garlic more efficient. Hey Dr. Greger I have a question about an over-consumption of some minerals such as manganese, iron, and copper. I entered what I generally eat into a website and it says I’m getting ~26mg of iron, ~11 mg of manganese, and ~5 mg of copper. I know you don’t want to drink a lot of hibiscus tea because of over-consumption. Are these safe levels? I also eat a lot of citrus which I’ve heard increases iron absorption. These levels don’t seem to high, but you can never be too safe.

    • mbglife

      Hi Kevin
      If you haven’t already seen them, you might want to watch some of the NF videos on iron, specifically, hemed (which comes from animal sources) vs non-hemed (from plant sources). Excess levels of hemed seem to stay with the body an increase risks to brain health; non-hemed seems to be safely eliminated with waste. You gotta love them plants. ;-)

      Mark G.

    • Mark is exactly right! When we eat minerals in the plant based form, any risks of overconsumption of one specific mineral is mitigated by other things contained inside the plant – fiber, primarily. Our bodies are also self-regulatory – moving to homeostasis and adjusting mineral levels through many biological processes. This is true from when we get our minerals from food sources (plant based sources). We don’t have the same benefit when we consume minerals from supplements, or of course, from any environmental exposure sources.

    • HemoDynamic, MD – NF Volunteer

      In my ten years of practice I have never seen a case of copper or manganese toxicity. I have only seen 3 cases of Iron toxicity known as hemochromatosis which is a very rare genetic disorder. I know there is concern over copper from copper pipes in houses with regards to Alheimers but Alzheimer’s is clearly most promoted but the Standard American diet which is loaded with saturated fat, trans fat, cholesterol and other inflammatory mediators. Eat plants and you will have very little to worry about because your body is very smart and controls the uptake of these minerals very efficiently.
      Also, yes eating iron rich foods with more acidic foods such as orange juice or lemon juice increases iron absorption. I don’t have time to provide any links but Dr. Gregor has some good resources on these topics on this website. I am on my trainer riding my bike right now or I would provide the links to this website. If someone could be so kind as to find those links and give this person those links I would greatly appreciate it. I hope this helps

      • Kevin

        Thanks! I appreciate the response. That means my iron intake should be more than good since none of it is heme iron. I was just trying to be careful. In that case it appears that you can’t eat too many leafy greens! I’ve been making two blueberry + lemon + flax seed + kale, spinach, chard, and arugula smoothies with at least every meal, and as a snack. Some of the meals are pumpkin pie-tatoes (sweet potatoes with pumpkin spice seasonings — courtesy of Dr. Greger), oatmeal with more blueberries and cinnamon (sometimes with peanut butter), etc.

        • HemoDynamic, MD – NF Volunteer

          Sounds delicious!!! I make delicious smoothies every morning for my family but no arugula–kids no likey! But they ‘secretly’ get a dose of health in that delicious smoothy.
          Back to the Copper story here is todays video addressing your very question! Alzheimer’s Disease, Copper, and Saturated Fat

          • Kevin

            Perfect timing. Thanks for your help. It seems like everything is fine if you’re on a whole foods plant based diet.

      • Cancer survivors–and there are a few of us here– should also be concerned about too much copper in their diet, according to cancer-nutrition specialist Dr. Jeanne Wallace (PhD in nutrition, not MD). Copper fuels angiogenesis, and cancer cells seem to sequester it. Unfortunately, many plant foods (including legumes, nuts, seeds and grains) all provide copper, to varying degrees, and although phytic acid binds many minerals, it doesn’t seem to bind copper in humans. For sources, see

        Fortunately, some phytonutrients do bind copper–including quercetin, myricetin, ellagic acid and EGCG. Myricetin and quercetin (and kaempferol, which seems to work with quercetin)all belong to a class of flavonoids, called flavonols, that is showing promise in the fight against cancer. They act as anti-oxidants in normal cells but as pro-oxidants in cancer cells–and Dr. Keith Block, an M.D. and diet-cancer specialist, suggests that may be because those flavonols bind to all the copper in cancer cells. The free radicals created then damage cancer cells, leading them down the road to suicide. For sources of info and sources of those flavonols, see

  • uma7

    Still on the edge of my seat from the DHA cliffhanger…

    • See the Doc’s note in the last video–waiting on a study to become public so I can share.

      • uma7

        Missed that, thanks.

    • Kevin

      At the end he did say he still recommends it for brain health (and I’m glad he did say it). So it’s not too much of a cliffhanger, but it’s still interesting to see what the next video will have.

  • alvarowier

    Hi dr. Greger/NF, I am reading how not to die (great book!) and I have noticed avocados are listed as green foods. I cut back on avocados when you published the “are avocados safe” videos (and was not entirely reassured by your update that avocados reduce prostate cancer risk, as I am not sure how to interpret the importance of one study on a specific disease). Has more research come out recently suggesting that avocados are safe or are there other reasons to believe persin toxicity is suppressed when consuming the whole fruit? thanks!

      • alvarowier

        I read the update but was unsure how to interpret it and if it can be extrapolated to avocados’ effect on other diseases/cancers etc. I guess avocados can be considered as safe in moderate amounts or it wouldn’t be in your book:)
        Thanks for the quick response and sorry for asking so many questions unrelated to the video!

      • Joe Caner

        Dr. Greger, It is good that avocados have been found to be protective against prostate cancer. How does this square with the in vitro study that shows that avocados induce chromosome damage when dripped onto white blood cell as outlined in you video “Are Avocados Bad for You?”

        Is there any evidence that avocados are selectively favoring carcinogenic over healthy cells for this chromosome destroying behavior?

        If so, avocados may very well be a benign natural chemo-like agent.

        • alvarowier

          This is exactly what I was thinking; chemotherapy also reduces prostate cancer, but that doesn’t make it “healthy”, but I think the crucial difference is (I just looked up and read the whole study) that this wasn’t an intervention-type study, but a cross-sectional population analysis(I think it’s called that): they checked for a correlation between avocado consumption and prostate cancer in a Jamaican population. So, assuming that didn’t just became available a month before the study, the study measures the long-term effects of avocado consumption. Chemotherapy doesn’t decrease long-term cancer risk (it increases it, as far as I know, though I’m no expert!), it only helps your body overcome the current cancer that has gotten out of (your body’s) hand.
          Still, would be nice if there was more research into this so it may be understood better.

        • michellevegan

          I think the science and logic, as I understand it, suggests that avocados should not be part of a weekly diet. Maybe even take 6 months off eating them. It is so easy nowadays to indulge in vegan foods that otherwise would never have been available and in bounty, in times past, such as the avocado. But the chromosome damage info. does seem to suggest longterm breaks from this fruit are prudent, and that decades of consistent consumption (lots of vegans doing it!) of avos could spell trouble.

          • Joe Caner

            I have always eaten avocados sparingly due to their high fat content. I now do so out of concern I have due to the study that was brought to my attention by Dr. Greger’s video that I’ve previously sited so my relationship has not appreciably changed towards them. It’s too bad that avocados are in the questionable category, but it is better to know the facts, and act accordingly.

          • Vege-tater

            I agree Michelle, with the mindless trip through modern produce aisles, we forget that in nature very little is going to be available pretty much year round, as it is now. Eating local and planting whatever you can is a great way to get a feel for what we should be mostly eating. Nuts and seeds used to come in some pretty tough packages, unlike now, so it was hard to eat too much even when you could get such high fat foods. I love the science too for the health hacks, but let nature guide me, as it has for millennia. (Yep I’m that old! LOL) Fast food fills faces but we’re forgetting about the depth of the nourishment of body and mind that comes from being involved with our food. I love the “Slow Food” movement!

      • robert

        Completely unrelated topic, but I wanted to thank you for “How Not to Die”. Despite following all of your videos for years including reading most of the comment sections, I wasn’t prepared for how well organized and presented the material was. There is so much to go over and incorporate into my diet that I am planning to reread the book right away! I have started adding 2 Tbsp of Hudderite beans (white beans) to my morning oatmeal and they not only blend in perfectly but with the ‘bean effect’ I am not getting that drop off in blood sugar before lunch. My oatmeal consists of 1 cup of thick rolled oats, 1 tsp goji berries, 1 Tbsp of ground flax, 1 tsp of Chia seed, frozen berries, seasonal fruit, hemp seed, walnuts and sunflower seeds and warm water.

        • peseta11

          Not clear to me if you have your rolled oats semi-)raw, but I find steel-cut soak well overnight in ~1T cider vinegar per cup warm water, only coming to a quick boil to be utterly edible.

  • Emma

    I loved your book “How Not To Die”!
    Regarding this video, I’m concerned if I should stop consuming garlic and onion altogether since I have a hereditary thrombocytopenia. My platelet count is about 76,000. It was so much lower as a kid by the way. Also worried if my future kids must avoid them if they have the same condition which is very likely. Thank you!

    • Dr.Jon_NF Volunteer

      Emma: Thrombocytopenia, as you know, is a condition where your platelet count is low. As I understand it from Dr. G’s video, the effects of garlic, and onions is similar to that of low-dose aspirin, in that they make platelets less “sticky”, i.e. less likely to clump together and form clots. Garlic doesn’t lower your platelet count, so I doubt you have to worry about eating garlic. Furthermore, your platelet count of 76,000 is not a dangerously low level. My recollection from when I was taking care of more hospitalized patients is that you only really have to worry about uncontrollable bleeding if your platelet count drops below about 5,000. I will check these facts and let you know if there’s been any update.

  • SoBelle

    Dr Greger, like 3-8% of the population i have Factor V Leiden (genetic blood clotting disorder)…. can you suggest safe and healthy ways to minimize the risks?

    • DrAlex_NF_Moderator

      SoBelle, you’ve asked a great question! As you eluded to Factor V Leiden is a genetic disorder which makes you more susceptible to clotting. This susceptibly can lead to a higher risk of a deep vein thrombosis (blood clot in the leg) and the potentially fatal pulmonary embolus (blood clot that has traveled lungs). A lot of people of who have Factor V Leiden are unaware…it’s only when something like a DVT/PE comes up that subsequent testing reveals the diagnosis of Factor V. If you look at the people who end up with the PEs and DVTs, it is usually folks who have modifiable risk factors who are getting them. They are usually folks that are obese, are immobile, and/or who smoke. We also see a higher incidence in people who are pregnant or who are on oral contraceptives. From my perspective, the best thing you can do for yourself if you have Factor V Leiden is to get rid of as many other risk factors for blood clots as you can…that includes eating a healthy diet to avoid obesity, staying as active as possible and avoid sitting for long periods of time (have you seen Dr. Greger’s interviews where he is walking on a treadmill throughout the entire interview?), and not smoking. I hope this helps a little.

      • SoBell

        Thank you…I have done my best to mitigate the other risks factors. I discovered I had Factor V Leiden when i was 24 yrs old, i developed a superficial clot in my arm while I was taking an oral contraceptive. Years later I had to have daily Heparin injections throughout my pregnancy. I was lucky I discovered my condition before pregnancy but sadly my good friend was not so lucky, she passed away at 8months pregnant.due to a pulmonary embolism. My question is more along the lines of….. will eating high amounts of cruciferous vegetables be harmful to me? Will eating tomatoes, garlic and onion help??? i have had a few superficial clots in the past and have been advised to take an asprin daily, which i am doing but I am not on warfrin and really want to avoid it as I get older, if possible.

  • HemoDynamic, MD – NF Volunteer

    In my ten years of practice I have never seen a case of copper or manganese toxicity. I have only seen 3 cases of Iron toxicity known as hemochromatosis which is a very rare genetic disorder. I know there is concern over copper from copper pipes in houses with regards to Alheimers but Alzheimer’s is clearly most promoted but the Standard American diet which is loaded with saturated fat, trans fat, cholesterol and other inflammatory mediators. Eat plants and you will have very little to worry about because your body is very smart and controls the uptake of these minerals very efficiently.
    Also, yes eating iron rich foods with more acidic foods such as orange juice or lemon juice increases iron absorption. I don’t have time to provide any links but Dr. Gregor has some good resources on these topics on this website. I am on my trainer riding my bike right now or I would provide the links to this website. If someone could be so kind as to find those links and give this person those links I would greatly appreciate it. I hope this helps

  • Nick Presidente

    This is interesting. I eat a lot of soups, stew, curries that are one pot meals, cooked on lower heat over longer periods than I make them into servings over the week, always a lot of good stuff in them, ginger, garlic, various onions and other veggies. I guess I overcook the hell out of them.

    I worry about the odor issues with raw garlic, and I won’t eat raw onion, so only occasionally eat any garlic in a dressing or hummus raw. I do chop up my veggies and the process can take over 10 mins.

    Not sure it is something I’m going to worry about though

    • That was actually my concern to. Whilst I don’t cook for as long as you do, I do like to slowly cook the garlic and onions (I prefer shallots) in water, for maybe 10-20 mins then add the rest of the ingredients (after having chopped and crushed those two for at least 10mins). So am I ruining their effect? I looks that way… :-/

      • Nick Presidente

        I generally use shallots too, didn’t want to get all fancy on people.

      • Onion researcher Dr. Irwin Goldman says that onions and shallots need to sit around after their cell walls have been broken for about a half hour so allinase enzymes can work their magic. To preserve their nutrition, onions and shallots should be cooked for 4 to 5 minutes max, he says. How to cook onions that quickly? I like a steam–saute technique. First, I saute onions in a dab of olive oil and lots of spices, then add some liquid, cover and steam. Any other ideas out there? For more of Goldman’s onion wisdom, see and

        • Thea

          Harriet: re: more ideas? I find that my chopped red onions cook perfectly in the microwave in exactly 3.5 to 4 minute. No water or oil is needed. Just put them directly in a microwave safe bowl and they cook perfectly, ending with a slightly translucent look and nicely sweet.

          • Thea,

            According to Phenol Explorer, microwaving onions decreases two important flavonoids –quercetin and kaempferol (the latter, considerably). See and Boiling also decreases quercetin in onions. See

            Unfortunately, Phenol Explorer has no data on the comparable effects of steaming onions. Has anybody come across those figures? I realize Phenol Explorer may not be the final word.

          • Thea

            Harriet: Thanks for the info. That doesn’t bother me, but it is interesting. Cooking decreases some nutrients and increases others. In general, I try to stick to known healthy cooking methods (ie, not frying…) and whole plants foods both raw and cooked, along with B12 pills of course. For the majority of healthy people (I believe that you work with people recovering from cancer who may have special needs), I think my goals are all that people need to worry about. Stressing about particular flavonoids seems unproductive. But I do thank you for your post. For someone else, that could be key information.

          • mossfoot


          • Thea

            mossfoot: I’m glad you asked! The overwhelming misinformation about microwaves that you find repeated again and again is a perfect example (for me anyway) on how the internet can go wrong. To me, this is what going ‘viral’ really is, because the result is so destructive. While I think the following site is often full of bad information in general, no one is wrong about everything. I think the following article does a fantastic job of debunking the microwave myths, complete with references, that I’m sure you have read about:
            Plus, Dr. Greger has some videos on microwaves that back up what the above article claims:
            The cautions for microwaving are: Stay away from plastic in the microwave. Skip the butter flavored microwave popcorn (see videos on NutritionFacts for this). Beware that the microwave can make food hot (duh) and create hot spots, including super heat water without looking like it. Keep in mind that microwaving meant heating the food. So, like other heating methods, some nutrients are destroyed and others are made more absorbable by the body. Over cooking can destroy more nutrients than lightly cooking.
            If you get a chance to read the article above from the first link, I would be curious to hear what you think of microwaves after reading that article and whether this response has helped you.

        • Thanks, Harriet.

          Ok, seems I’m not that far off the ideal. I do saute in just water after having crushed/chopped the garlic and onion; oftentimes it’s 20-30mins before any heat is introduced. And I don’t tend to cook for long at a high temp. I usually add other ingredients to it that I heat up but not so they’re piping hot; the beauty of a plant based vegan diet means you rarely have to worry about having foods piping hit to avoid poisoning yourself with nasty meat pathogens and bacteria.

          • I also like to let the cut garlic sit in a dab of high quality evoo before using it. I find garlic easier to digest that way. Maybe that’s because some of garlic’s compounds are soluble in fat; others, soluble in water.

    • George

      Nick: What I do is to add the garlic, chopped about 15 minutes earlier, at the last moment, a minute or so before turning the heat off.

  • guest

    From what I gather from the video, garlic powder is effective, but is it as effective as fresh garlic? (Allicin is not a stable compound even at room temperature, so I wouldn’t expect garlic powder to contain a lot of allicin.)

  • Kathryn

    Will adding granulated or powdered garlic or onion after cooking have the same effect as adding raw?

    • pm

      Good question. I would like to know this too.

    • Kathryn, is there a reason that you prefer powered garlic over the whole food form? Some people don’t like the taste of garlic – perhaps you are one of them! My suggestion is you try my trick: I smash the garlic clove with a knife, then mince it super fine and then use it to make my own salad dressing or to cook. With Dr G’s findings from today, I’ll smash, then wait 10 minutes to let the alliinase and the alliin make allicin!

      • Paul

        It might not be a preference, sometimes I want to cook something with garlic and find that I’m out of fresh and don’t feel like running up the block to buy a bulb. :)

      • Kathryn

        I love the taste of garlic and use lots but I don’t always have fresh cloves. Dried garlic has a strong taste. I mainly eat it in soups and stews where I add it at the start of cooking and I find the dried garlic works great there. Although I eat a WFPB diet with no oil, I was not thinking of garlic as a whole food but as a flavoring – I use other dried herbs and spices also. I could add a raw garlic garnish at the time of serving but that would be a little strange in these soups and stews so I was wondering if a boost of dried garlic at serving would work to make allicin.

        • A Newton PhD RD_NF Mod

          Hi Kathryn, great question. I did a quick search and could only find one, very “dated” study looking at the efficacy of dried garlic. Their concluding statement was, “if there is any effect of garlic on the parameters measured, it is not apparent when using a dried preparation in the dosage studied.” The link to the study is here (, and it’s not full text and published in an obscure journal, so I would take their conclusion with caution. I do know though that in dried preparations a number of nutrients can be lost, so I would err on the side of fresh or prepared in the manner discussed in the video. I will continue to search the literature though for a more current investigation into dried products.

  • Rick Calhoun

    What is the efficacy commercially available deodorized garlic supplements?

    • pm

      I take supplements and would like to know this as well.

      • A Newton PhD RD_NF Mod

        PM, please see my reply to Rick above.

    • A Newton PhD RD_NF Mod

      Hi Rick, commercial preparations of garlic have been standardized to have a fixed alliin and allicin content, and case studies of individuals taking very high doses of odorless garlic tablets have shown increased platelet coagulation defects (i.e. hemorrhage). I believe they are efficacious. However, it might depend on the supplement company, since they are not heavily regulated by the FDA it’s hard to determine if you are getting exactly what is purported on the label.

  • Dr. Greger shares in the above video that 1/4 teaspoon of garlic powder per day is helpful with promotion of more flexible arteries. He summarizes the effects of garlic in a blog post from a few years ago: Something interesting about garlic supplements is the lack of evidence based reviews of efficacy. Dr. Greger’s post makes sense: the efficacy of garlic is the same by eating it raw, or crushing it, waiting 10 minutes, then cooking it. The whole food form wins! You might benefit from the Center for Science in Public Interest (CSPI) report on garlic supplements – the science does not seem to support the supplement form.

  • GEBrand

    For garlic lovers only:
    When I’m cooking with garlic I press the garlic in a garlic press and let it sit there while I prepare the rest of the meal. This allows the garlic plenty of time to develop its magic. Then, a minute or two before serving the food, I add the garlic. It is only the residual heat that ‘cooks’ the garlic. When cooking pasta, I add the already pressed garlic directly to the cooked, drained linguini and then add whatever sauce. The garlic flavor is stronger of course – hence my warning “For garlic lovers only”.

    • Paul

      I’ve never used a garlic press since it’s a one-use item, would rather not have the clutter. But chopping garlic usually results in it sitting there waiting for the rest of the ingredients and recipe to begin, so I’ve never worried about the “10 minutes” or whatever. I just throw it in when I’m ready. :) I’m cooking purple potatoes right now, threw some chopped garlic in the cooking water and will mash it directly into the potatoes when done. Mashed potatoes, side of steamed spinach and bean sprouts with lemon and garlic, and a Caesar salad.

  • Guest

    Well, I eat a lot of fresh garlic and I’m as healthy as can be, but I have one problem. I lost all my friends. One of them told me privately that I smell too “garlicky”, not only my breath but it seems to be coming out of my skin pores too! Anyone know of a way to cut out the odor and still get the benefits of eating fresh garlic. Or is there a form of garlic that provides the benefits but doesn’t cause a body odor?

    • Vege-tater

      I heard parsley can help, and is full of all kinds of benefits in itself!

    • DrAlex_NF_Moderator

      Very common problem with garlic. Not only can it hang around in your breath…but also in your sweat. Parsley, as mentioned by Vege-tater, is one option, and there are others, such as chewing on mint leaves, drinking green tea, or even eating spinach. It’s a plus that all those options are good for you, too! You might now always have some mint leaves on you to chew on after eating garlic so eating an apple is also another option. There is a component of garlic (that smells…) that is not broken down naturally by us. Apples, mint leaves, green tea, and spinach seem to have that missing enzyme to help break that down. There in an article from the Journal of Food Science in 2014 that gives more details if you are interested: Deodorization of garlic breath volatiles by food and food components
      Hope this helps!

      • Guest

        Wow, thanks so much. I never knew that. I had heard about parsley, but the other techniques are new to me.

    • TheHulk

      Well they get used to it eventually. But I lost one very good enemy of mine with Garlic and that is Mosquitoes :). Here in India, there are lot of mosquitoes but they all stay away from me the day I started having Garlic first thing in the morning :) . Also chewing some Fennel seeds negate the garlic smell in breath.

    • Joe Caner

      Garlic is for lovers. Perhaps, you can strike up spicy relationships with saucy individuals with similar culinary proclivities while chewing on fennel seeds, mint leaves, parsley and spinach to hang onto you existing circle of friends. ;)

      • Guest

        Thanks, I never knew about the fennel seeds. I’ll have to try that. If none of this works, I’ll just hang around my garlicky friends ;-)

    • I heard recently that swishing mustard around in your mouth helps. Tell us if it works for you!

  • Oh that is a bummer! I know that is one reason people turn to deodorized supplements, in hopes of getting garlic’s benefits without the stink! I’m wondering about GEBrand’s suggestion below of using the garlic press, letting it sit, then throwing it in at the last minutes of cooking? Is it possible you eat too much raw garlic? You can certainly get the health benefits of garlic with cooked forms, as Dr G shows today.
    Maybe you need to start a raw garlic eating MeetUp! That might be fun! Let me know how things go.

    • Wade Patton

      I have smelled garlic on two people, in my 49 years. It wasn’t initially obvious to me what the smell was, but I figured it out and recalled the aroma from many years earlier (hence the “two people”) I hope I never smelled that way to anyone else and no one has ever mentioned it, as I’ve always been a garlic hound.

      I like it raw I like it cooked and include it in nearly everything. I ate 2 or 3 small cloves watching this video.

      I WANT scientific research on why some smell and some do not. MAYBE I was “low” in my garlic consumption when I smelled it on others and thus was “sensitive” to the smell?

      Maybe simplest thing (assuming we don’t smell it if we’re eating it) is for EVERYONE to eat a lot of garlic and then we’ll all be used to any smells and get along just swimmingly and BE HEALTHY all at the same time. Plus the flavor thing.

  • walterbyrd

    Waiting ten minutes does not seem to make much difference. If I am understanding the chart correctly.

    • A Newton PhD RD_NF Mod

      Yes, the chart was a little confusing, but the article that did that evaluation concluded that, “garlic crushed and then allowed to
      stand for 10 min before microwaving for 60 s had the same anticarcinogenic activity as raw crushed garlic, whereas uncrushed 60-s-microwaved garlic had no anticarcinogenic properties in rats (not different from the untreated group).” So, it’s important to note that these findings were looking at a cancer model, not atherosclerosis and also the method of cooking was microwave; however, they were still looking at at alliinase activity.

      Edit: here is the link to the study for your review.

      • Thea

        A Newton: I found the chart confusing myself. Thanks a bunch for this clarification.

  • easyout

    Hey Dr. Greger, is there a reference for all vegetables, as far as up-to-date science on what micro-nutrients are in them, do the micro-nutrients last while cooking, what the micro-nutrients do for the body, etc. Sure would be nice to have a reference instead for trying to look for each study or fact on each specific vege/fruit/herb.

    • A Newton PhD RD_NF Mod

      Hi easyout, my co-moderator Lisa just brought up a great resource on micronutrients from Oregon State University. This website ( will provide you with a list of micronutrients and their foods sources.

    • Tom Goff

      The US National Nutrient Database is also a great resource. It gives the macro and micro nutrient breakdown of a huge range of foods including, in many cases, both the uncooked and cooked versions.

      There is also a free searchable data base which presents this same data in a graphic format and is quite helpful. However, it is a commercial site and I think the data it uses comes from an older version of the US National Nutrient Database.

      • easyout

        Thanks Tom, it’s really helpful to get positive input/answers from commentators. Very informative natural health sites like this pose just as many questions as comments.

  • Ronald Green
  • Matthew Smith

    Is it the Sulfur? Garlic, mustards, and alliums are very good for you. Sulfur is the third most abundant mineral in the body, and largely without a source of intake. Perhaps it’s metabolism is different than that of mitochondria. Perhaps Sulfur is used by the Rods in the cell, the “Centrioles.”

  • David Hochstettler

    so I am at a loss now what to do . Once a week I have been putting a bulb of garlic in the food processor and steaming it for 5 minutes with my chopped greens carrots and beet. Should I scatter it over the greens after I steam them or should I go with the garlic powder and put a 1/4 tsp in with my daily refrigerated salad (greens, beans, cooked whole grains and potatoes

    • Lonestar

      You could premake a kind of “dressing” using your garlic in raw form, and experiment with the recipe so it tastes right without needing to do the steaming.

    • Thanks for your question David! I am a Registered Dietitian and I have recently joined NF as a Moderator.

      According to the study mentioned by Dr Greger, the best way to get the most out of garlic:

      – crush it first & save some of the raw juice that comes out in this process
      – wait for 10min and then start the cooking process
      – and as you are steaming, add a bit of that extra raw garlic juice into the mixture

      Hope it helps!

  • Lee

    This research seems to confirm something I read in the book, “Left for Dead” (1992) by Dick Quinn. In it, he cites numerous plants and herbs that are beneficial for heart disease (including cayenne, garlic, onions, ginger). One reference that particularly struck me was a 1966 study by researchers (N.N, Gupta) at Lucknow University in India that claimed that eating 2 oz. onions with a very high saturated-fat meal ameliorated the effects of it, including ‘platelet clumping’, and inhibited blood clotting and lowers cholesterol. Was only able to find the title on PubMed, but no abstract. As reported in this video, garlic and onions do have ‘anti-platelet’ activity and seems to confirm the claim in Mr. Quinn’s book, and N.N. Gupta’s research 50 years ago. Would love to see the original research paper! (hint, hint, Dr. Greger if your team can get access to it).

  • Anan

    The stay mentioned in the video was done with garlic powder… What’s your opinion on powder vs raw for health benefits?
    Is there any benefit in consuming powder garlic ?

    • NFModeratorKatie

      Hello! Yes, garlic powder can be beneficial too! Some of the research from this video supports that those who consume just less than a quarter teaspoon of garlic powder a day, appear to have less stiffness in their aortas. Dr. Greger also points out some of the many benefits to using raw garlic as well – which should be good news for garlic lovers everywhere!

  • CommanderBill3

    This is the sort of information I go to this website for. I have been consuming garlic for years for it supposed health benefits. However I have been cooking the chopped garlic in my morning breakfast concoction. I will now start consuming the stuff raw.

    I have a question on what is recommended dosage?

  • VegRunner66

    We usually use the the chopped garlic in the jar…how does his figure into it all??

    • NFModeratorKatie

      Hello! I usually recommend fresh garlic. I understand buying minced garlic is convenient. However, there’s a good chance it’s being stored in added oils and additives.

      • VegRunner66

        Thanks Katie…but what I mean is since it’s already pre-chopped, will it still have a large amount of platelet activation. Thanks. (p.s. no oil in the garlic but does have phosphoric acid)

        • NFModeratorKatie

          So sorry for the confusion on my part! We know that when we chop garlic, wait ten minutes, and then cook that some of the antiplatelet activity is retained a bit longer. But, I’m not sure if there’s an ideal time limit for this. Let me see what else I can find. In the meantime, I’ll leave your question open for other moderators to provide additional feedback. Thanks again for your question!

  • lgking

    Regarding Garlic consumption, I think the whole purpose of a WFPB diet is to eat and consume things in their natural state (fresh, raw) to receive the greatest amount of benefit. To me, that includes my garlic. Since discovering that breaking down plant cell walls is enhanced by the use of a blender, I have been ‘liquefying’ my raw salads in a blender and also adding my 4-5 large chopped raw garlic cloves, chopped raw onion, chopped raw tuneric root, chopped raw ginger root, and Pineapple Vinegar into my salad/now sauce to pour over my fresh cooked (not canned) black beans and Thai Jasmine brown rice. I have since discovered that this raw-sauce preparation has minimized my garlic ‘smell’ to others. I personally think it has something to do with the soaking of the garlic with the vinegar for 15 minutes before blending. But whatever, it seems to be working for me. For what it’s worth.

  • Joel Santos

    So how much garlic should we consume for optimal health? :)

  • Sebastian Tristan

    OK. So if I understand correctly, the healthiest way to consume garlic and onion is raw?

    • NFModeratorKatie

      There are so many delicious and healthy ways to consume garlic! For protection against cardiovascular diseases, the best way to consume is either raw, crush or chop – wait ten minutes then cook it, or add a little raw garlic juice to cooked garlic. Here’s another video on garlic that you might find interesting: Cancer, Interrupted: Garlic & Flavonoids. Happy cooking!

    • For onions–Raw is definitely good. You should cut them somewhat (to break their cell walls) and then let them sit a half hour or so in order for the allinase enzymes to get to work, says onion researcher Dr. Irwin Goldman.

      As for cooking onions, there are some studies showing that quercetin–the important flavonol that concentrates in the outer layers of onions–may improve with some forms of cooking. For example:

      baking 15 min (176C)–quercetin increases slightly (7%)

      sauteeing 5 min (93C)–quercetin increases 25%

      but boiling– quercetin leeches into cooking water

      steaming– quercetin presumably retained, but steaming for longer than 3-6 minutes destroys anti-platelet action and for longer than ten minutes, makes platelets sticky!

      See Goldman’s study at When I interviewed him, he suggested that if you cook onions, keep cooking time short (4-5 minutes max.)

      Based on all this info, I’ve become a fan of the saute-steam method of cooking onions. First, I saute them in a little olive oil and spices very briefly, then add a little liquid (water, tomato sauce or olive paste mixed with water), cover and steam for a couple of minutes. As long as you cut the onions small enough, they’ll cook in no time. Here’s a “messipe” for Indalian Onions. Let me know what you think.

  • Ray Tajoma

    I am a strong believer in eating raw foods. I boil chopped potatoes, onions and garlic for 2 minutes and eat them. You don’t have to boil for long time to get rid of the extreme sharp sting in the mouth (2-4 minutes is sufficient). 2-3 minutes of boiling will also soften the potatoes.

  • Joshua Pritikin

    Kenji López-Alt found a relevant paper. See Figure 5: Effect of pH on activities of free and immobilized alliinase. Relative activities were calculated by using the highest activity of free and immobilized alliinase as 100%, respectively.

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  • Vegan4health

    I am really annoyed with the Petri dish and test tube “tests” where a substance is dropped on a tissue or cell. It does not translate ever to what happens to the substance when ingested and metabolically processed. I really don’t want to hear about these things again. It rubbish that clogs my brain. I understand that it points a researcher in a possible direction but it is not useful information to me.

  • johannes

    Dear Dr. Greger,

    I suggest that you also look into the downside effects of garlic as taught by ancient eastern science.
    Garlic has some good effects like helping women in premature
    labor etc but there are negative effects too.
    There are a few facts regarding garlic, which are not known to western
    science. In the East, it is known for thousands of years that garlic has
    a paralyzing effect, affects the clarity of mind, leads to constant
    headaches, attention deficit disorder, and can dissolve the blood
    vessels particularly in the elderly which can lead to blood clots with
    possible serious consequences like stroke.

    garlic can kill bacteria, it has no effect on viruses. It is definitely
    better to have and build a healthy immune system which can deal with
    bacteria and viruses such as the flu. This way you won’t need any help
    from garlic and things alike.

    proved scientifically harmful and even deadly for dogs and cats. The
    toxicity for human beings was accidentally discovered when calibrating
    EEG biofeedback equipment.

    force pilots and flight doctors decades ago knew they must not touch
    garlic 72 hours before they fly an airplane because their reaction time
    would be doubled or tripled. Studies at Stanford University confirmed
    that garlic desynchronizes brain waves.

    and Leek species: Onions are harmful to the lungs; garlic is harmful to
    blood vessels in the elderly, and therefore dangerous for the heart and
    brain (possibility of stroke). Leek is harmful to the spleen, chives
    for the liver, and spring onions for the kidneys. In addition to
    offensive breath and body odor, these plants can cause exacerbation of
    restlessness, anxiety, and aggression. This and above mentioned
    provocative substances (salt and spices, verse 9 above- from my book)
    are physically, emotionally, mentally, and spiritually harmful and
    disturb the intestinal flora and thus the absorption of vitamin B12.

    In his book The Raw Food Diet
    and other healthy habits

    Your Questions Answered Don Bennett is devoting a few pages on the research done on garlic, confirming the above info.

    Here the ancient story about the origin of garlic and more.

    my experience recently: A friend of mine (in his 70s) never took
    garlic. Then a health practitioner recommended him garlic which he took.
    A few weeks later he got a stroke and is paralysed since then. Garlic
    is known as a blood thinner and not only dissolves blood clots but can
    also damage or dissolve thin artery walls in the elderly – leading to
    stroke. May be more research needs to be done on the dangers of blood

    Best wishes


  • mlev5

    For simplicity sake, if I didn’t want to eat raw or cooked garlic, but just wanted to do what they did in the study to gain the health effects..

    “Those who consume garlic, though, just less than a quarter teaspoon of garlic powder a day, appear to have less stiffness in their aortas”.
    Can anyone offer any guidance on how to consume the garlic powder – for ex. are there different kinds of garlic powder? Is one better than the other? Any brand preference? Should it be taken with meals or on empty stomach? etc.
    Thank you!